What, for a painter, surpasses the nobility of the human figure? Why, several human figures—or so we might gather, thumbing through any history book of western art. So many of the “mega-hits,” from Leonardo’s “Last Supper” to “Night Watch” to “ Guernica ,” consist of groups of strategically interacting people. No wonder ambitious painters continue to be drawn to such heroic feats of composition.

The trouble is if you’re not Leonardo, those half-dozen figures disporting across a landscape or interior are liable to look less like individuals with inner lives than marionettes jerking on strings. With dismaying speed, epic poetry can turn into traffic engineering.

Graham Nickson is one painter who rises to these challenges and prevails on his own terms–though with such bristling intensity that visitors to his ninth exhibition at Salander may at times feel they’re getting the same workout as his straining figures. The paintings, some of them huge and the product of over two decades of work, mostly depict a favorite theme, bathers at the shore. All reveal the familiar, formidable attack with strident colors and tightly knit dramas of pose and counterpose.

Although performing natural tasks in fairly ordinary settings, his figures gesture with the deliberateness of Neoclassical history paintings. Picture that magisterially raised arm in David’s “Death of Socrates.” (It’s no coincidence that Mr. Nickson, now in his late 50s, is Dean of the New York Studio School and originator of its grueling Drawing Marathon.)

Despite his turgid color, the artist’s drawing dominates in these paintings. But in many areas, his hues vibrantly support the energy of his contours, lending a remarkable presence to gestures and light. In the lower left section of the immense “Edge Bathers” (1983-2005), a kneeling figure leans forward, placing her forearms on the towel spread before her. (She doesn’t look exactly comfortable, but then “comfort” here is an alien concept.) The artist energizes this inspired construction—taut angles of elbows springing from the great arc of a foreshortened back—with a few perfectly calibrated hues: a deep, dusky scarlet for the shadowed towel, rich purple on shaded flesh, vivid lights for their illuminated counterparts. Above, with a rare touch of mischief, the artist has placed a single lick of lightning against the implacable horizon.

In “Theoria” (1989-2005), contours and hues combine again to lend part of the image a wonderfully specific vitality. A standing woman stares upward at a clutch of balloons, her tipped head holding powerfully at our exact eye level. Her vertical form stretches below with monumental sureness, its length measured out by opposing notations of bathing suit, ribs, and knees. The sand at her feet seems ponderously far from the head, in large part because of subtle pressures of color: though both are varieties of orange, the sand quietly throbs as if absorbent of sunlight, while the skintones alongside radiate light, and it’s a marvel how this subtle difference urges the figure’s vertical rise out of flatness.

Both of these paintings are made up of smaller panels that might be almost complete works on their own. In fact, this process of accretion appears to form the basis of Mr. Nickson’s working method; the main elements seem to grow, crystal-like, from inner cores, a technique especially effective for the dense modeling of figures.

Be sure not to overlook two of the artist’s more modest efforts. One of two landscapes above the desk, the spacious “Dark Island Dawn, Jade Sea,” (2004) features dark blue/violet ripples of clouds climbing into space above a luminous blue-green sea. The smallish image reminds us of the looser direction Mr. Nickson has pursued for many years in the medium of watercolor.

One side effect of the highly deliberated drawing in his figure paintings is that the hues, while occupying aggressive points on a color wheel, are often surprisingly passive when it comes to a composition’s largest rhythms. Intensity of color and pictorial presence are not necessarily the same thing. In “Reflection,” (1989-2005) light pours through a window into a darkened interior, leaving a sequence of lights on a woman’s hair and the wall behind. Unlike that striking passage of sand-to-sunlit-flesh in “Theoria,” these patches, though varying in hue, have exactly the same pictorial weight. Rhythmically the hair has just as much of a rapport with the wall as with the rest of the figure.

A colorist like Matisse or Veronese hierarchizes his color, particularizing with weights of hue each step of the movement from the largest ground/sky divisions down to the subject’s details. Mr. Nickson’s potent drawing, though, tends to be the sole determinant of scale and focus, leaving certain passages of color in a kind of compositional purgatory. To the left of that powerful vertical figure in “Theoria” is another individual clutching an inflatable whale. Here the same electric pinks and stolid purples describe elements of both man and whale, flattening and completely deflating their presence in the surrounding color sequences. The result is so complete as to seem deliberate—and one wants to cry out: Enough drawing! Let color speak!

“Sandbar Bathers” (1999-2005), too, at once rewards and tries the viewer. Here, the artist beautifully renders the dynamic pose of a woman stretching a towel behind her back. Her arms angle vigorously through the turgid orange of fabric, opposing the subtle tilt of hips. Concise drawing and vibrant hue reinforce each other with a kind of classical muscularity. But move to the figures on either side, and color practically disappears as a compositional factor; the drawing explains complex overlappings of forms, but the colors mumble and dither. In fact, one has to look twice at this thirteen–foot wide canvas to register its overarching concept of space–figures planted in foreground, sandbar arcing behind–because it’s captured only in its drawing.

This should all be viewed, of course, in the light of the age-old debate about the primacy of color or drawing. Do you aspire to Ingres’ probity of line, or Delacroix’s eloquence of color? Mr. Nickson seems quite unapologetic about his choice.

But before resigning yourself to this fact, take a peek at the two rather casually painted figures airing a green towel on that distant sandbar. Their hues hold their places with the limpid authority one finds in the “Jade Sea” landscape, and it’s a bit of painting all the more striking because it seems an afterthought.

The artist’s intentions for drawing are evident in every square inch of his canvases, but his color—in-your-face, but elusive; vital here, disconnected there—remains an enigma. It’s all part of these uningratiating, forceful paintings—and explains, perhaps, why they’re so intriguing.

*****

In the first-floor gallery at Salander, the paintings of Giorgio Cavallon (1904-1989) are considerably lower-keyed. More joyful in execution and milder in ambition, these painterly abstractions have an immediate, comparatively innocent appeal. But they reward prolonged looking.

The artist uses a lively range of color to animate compositions of slightly rough rectangles with occasionally rounded forms. His technique is unaffected, as if the business-like brushstrokes were simply what the artist found adequate for his purposes. His goal, on the visual evidence, was focused and consistent: the uncovering of innate qualities of color and form and the movements between them. This the paintings achieve with aplomb.

There’s no doubt about the artist’s influences. A native of Italy , he immigrated to the United States in 1920, and shortly began studying under Charles Hawthorne. But it’s the impact of Hans Hofmann, with whom he studied for almost a decade in the 30s and 40s, that rings through every painting here. Countless artists may have passed through Hofmann’s schools, but Mr. Cavallon’s paintings, with their uneven blocks of color, are especially close to his teacher’s stylistically.

Mr. Cavallon has a gentler touch, and seems more inclined to layer colors in subtle veils, but one finds the same sense of exploring, of proceeding from hunches and seeing where they lead. The eleven paintings here amount to a survey of the last four decades of work, and one can trace his steady development within the lyrical confines he set for himself.

A work from 1948 (untitled, like almost every painting in the exhibition) neatly shows off the pulsating energy of the gridded patterns he favored in the 40s. There may well be a hundred different colors in this painting, each confined to its own cell but reacting in a distinct way to its neighbors: eclipsing it, shouldering against it, or wedging or slipping behind. An even-handed simmer of color-forms on the left third of the canvas evolves into a more unsettled rhythm at the center, with some forms lengthening and dominating in size. At far right, the match-ups have become more uneven still: a sizeable blandly off-white rectangle tussles with a fuchsia-hued ribbon bracketing it on two sides, neither willing to yield.

Several canvases from the 50s show how the artist began placing his colored forms against white fields. The pale backgrounds, quietly throbbing from many underlying tints, lend a slightly otherworldly aspect. Looser and broader shapes appear in later decades. A large painting from 1988, the year before his death, shows him still composing at full speed.

Mr. Cavallon exhibited extensively during his lifetime and his work is in the collection of several major museums, but he didn’t enjoy the level of fame of some of his colleagues. The temperament behind these paintings is one of unassuming earnestness, and this alone—never mind the parade of attention-hogging “isms” in the last half-century—would be enough to relegate a painter to the “under-appreciated” category. Judging from these plain-spoken but articulate paintings, he deserves better.